From Fedora Project Wiki
Line 158: Line 158:


<!-- If you cannot complete your feature by the final development freeze, what is the backup plan?  This might be as simple as "Revert the shipped configuration".  Or it might not (e.g. rebuilding a number of dependent packages).  If you feature is not completed in time we want to assure others that other parts of Fedora will not be in jeopardy.  -->
<!-- If you cannot complete your feature by the final development freeze, what is the backup plan?  This might be as simple as "Revert the shipped configuration".  Or it might not (e.g. rebuilding a number of dependent packages).  If you feature is not completed in time we want to assure others that other parts of Fedora will not be in jeopardy.  -->
* Contingency mechanism: (What to do?  Who will do it?) N/A (not a System Wide Change) <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
* Contingency mechanism: Prepare a kernel with the original 64k config, install it on the build server, rebuild all the packages for this architecture <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
<!-- When is the last time the contingency mechanism can be put in place?  This will typically be the beta freeze. -->
<!-- When is the last time the contingency mechanism can be put in place?  This will typically be the beta freeze. -->
* Contingency deadline: N/A (not a System Wide Change) <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
* Contingency deadline: whenever the last time for a full rebuild or kernel change is possible <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
<!-- Does finishing this feature block the release, or can we ship with the feature in incomplete state? -->
<!-- Does finishing this feature block the release, or can we ship with the feature in incomplete state? -->
* Blocks release? N/A (not a System Wide Change), Yes/No <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
* Blocks release? Yes, full rebuild of all packages must be completed before release <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
* Blocks product? product <!-- Applicable for Changes that blocks specific product release/Fedora.next -->
* Blocks product? product <!-- Applicable for Changes that blocks specific product release/Fedora.next -->



Revision as of 20:31, 11 January 2021


POWER 4k page size

Summary

On ppc64le, the kernel is currently compiled for 64k page size.

This change proposes using the more common 4k page size.

Some HPC workloads may be disadvantaged slightly. Workstation users are likely to encounter fewer bugs.

Some things, like the AMD Radeon GPU drivers, firmware or related code, appear to be completely non-functional on the 64k page size. Insufficient upstream developers are testing such issues on this architecture.

Owner

Current status

  • Targeted release: Fedora 34
  • Last updated: 2021-01-11
  • FESCo issue: <will be assigned by the Wrangler>
  • Tracker bug: <will be assigned by the Wrangler>
  • Release notes tracker: <will be assigned by the Wrangler>

Detailed Description

Feedback

Discussed several times on devel, latest here

discussed upstream in the Raptor forum

Benefit to Fedora

Better first impression for users of ppc64le workstations.

Users can focus on reporting ppc64le bugs without being sidetracked by page size bugs.

Scope

  • Other developers: please volunteer by adding your name here
  • Release engineering: #9939 (a check of an impact with Release Engineering is needed)
  • Policies and guidelines: no, as it is an arch-specific issues, most other architectures already have a 4k page size
  • Trademark approval: N/A (not needed for this Change)
  • Alignment with Objectives: none of the current objectives relate to this change

Upgrade/compatibility impact

N/A (not a System Wide Change)

How To Test

User Experience

Dependencies

N/A (not a System Wide Change)

Contingency Plan

  • Contingency mechanism: Prepare a kernel with the original 64k config, install it on the build server, rebuild all the packages for this architecture
  • Contingency deadline: whenever the last time for a full rebuild or kernel change is possible
  • Blocks release? Yes, full rebuild of all packages must be completed before release
  • Blocks product? product

Documentation

Release Notes